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Pregnancy Casting

Pregnancy Casting and other Life Casting

It might seem strange to some of you, but we often get
requests for information regarding pregnancy casting. Sometimes
we hear of people using dangerous techniques, but more often
we get questions that reveal confusion regarding the techniques
that are possible. Rather than confuse you even more, please
let me explain three methods with their pros and cons, and let
you decide what you want to do. These methods may also be
used for other life casting. We will start with the highest-quality
casting first:

Method 1: Alginate/HydroCal
White

A very soft material called alginate is put on the skin; after
it sets it is rubbery, but still delicate. A shell of plaster
bandages is put over this layer. The shell helps to keep the
alginate from flopping around after it has been taken off. These
two layers are taken off together and form a bowl that is an
exact negative of the body part. HydroCal White, which is a strong,
high-quality plaster-like material, is poured into this bowl
and moved around to remove all of the air pockets. After the
HydroCal White has set, the alginate and plaster bandages are
removed and thrown away, as they can only be used once. PROS:
This is the most gentle method, and will give you excellent details,
right down to every pore and blemish. Body hair is no problem
as alginate will gently pull off of hair. CONS: This process
is expensive compared to other techniques; it also takes the
most time, which can be exhausting to the model.

Note: Plasters other than HydroCal White may be used in
this method. See "About Plaster" below.

Method 2: Moulage

Moulage is melted in a double-boiler and brushed onto the body.
Moulage melts at a very low temperature and is warm to the skin.
As it cools it forms a layer much like the alginate. All subsequent
processes are the same as Method 1.

PROS: Costs less than
the alginate process because the moulage can be reused.

CONS:
Safety in heating the moulage is always an issue, plus the thought
of all the other people the moulage has been on makes moulage
seem rather unsanitary.

Note: Plasters other than HydroCal White may be used in
this method. See "About Plaster" below.

Method 3: Plaster Bandage

In this process, plaster bandages are used directly on the skin.
Unlike the other processes, this plaster bandage shell is the
finished piece. This leaves only the form of the body casting,
rather than the wonderful details the other methods provide.
Because you are using a plaster product, the model must be shaved
bare, including the finest down-hair. Plaster will grab hold
of every surviving hair and yank it out when the time comes.

PROS: Much faster and cheaper than the other methods.

CONS: Must shave the skin, details are lost.

Danger!
The idea of using plaster bandages always leads to the
question, "Why don't we just use regular plaster?"
If you've tried it before you know the answer is simple. Solid
plaster is very tenacious; sometimes your bone structure can
be locked into a solid plaster mass. Plaster bandages are thin
and CAN be pried off in case there is a problem. Another problem
with solid plaster is the heat generated when the plaster hardens.
This can cause up to second degree burns. Don't use solid plaster
directly on the skin under any conditions. It is only a popular
misconception that this is what is done in Hollywood. Professionals
use moulage, alginate, or if the budget permits, laser body scans.

How Much Material?

The next logical question about casting has to do with how much
material is needed. This can vary dramatically with you, your
technique, your model, and if you are clumsy like me.

Recommendations

Prosthetic Alginate
(Method 1):
Front of a face, 1/3 lb.
Full Face and neck, 1/2 lb.
Full head, 1 to 3 lbs.
Full head, neck and shoulders, 3 to 5 lbs.
For other parts of the body, you generally want to cover the
body area with an alginate layer from 1/4" to 3/8"
thick. It takes about 1/3 lb. of alginate to cover the area of
a standard handkerchief in this thickness. Remember that if you
put it on too thick, the alginate will cause the tissue to sag,
like excessive gravity; if you put it on too thin, the alginate
will have thin spots which will break or tear apart easily.

Moulage (Method
2):
Front of a face, 2 lbs.
Full Face and neck, 4 lbs.
Full head, 5 lbs. min.
Full head, neck and shoulders, 10 to 15 lbs.
For other parts of the body, figure 1/2 pound covers an area
about the size of a standard handkerchief. Moulage is much more
dense than alginate so sagging can be more of a problem.

HydroCal White
or other plasters (Methods 1 and 2):
There's no set method of calculating the amount of plaster you
need. Experience tells us that you will probably use everything
you mix anyway.

Plaster Bandage
(all methods):
Note: two to three layers or more is best.
Front of face, one 4" plaster bandage
Full Face and neck, 1 1/2 to 2 6" plaster bandages
Full head, about 12 6" plaster bandages
For other parts of the body, figure the square footage of the
area you want to cast and compare this with the square footage
of the plaster bandage you want to use. Use a minimum of three
layers and roll the edge (Like the rolled edge of a cooking pot)
for much more strength. Remember that the plaster bandages don't
just have to hold the alginate, they have to support the HydroCal
White or other plaster that you will be putting into the mold.
Strength is not of as much importance if a plaster bandage cast
is your finished product (Method 3).

About Plaster (More than you'll ever want to know)

Believe it or not, not all plaster is plaster. If you want a
fragile and inexpensive body cast, use "Casting" plaster.
You can buy it at your local hardware store or craft store for
a fraction of the shipping cost to get it from me.

For tummy casting, we recommend HydroCal White for several
reasons. First, it is much stronger than plaster; the psi (pounds
per square inch) of White is about 9,000 psi compared to Plaster
of Paris at 2,400 psi. This gives White a "stone"-like
feel. In the mold, I like to shape the White into a hollow bowl
form to cut down on weight and to give the finished product a
more artistic appearance. It takes about 3 to 5 lbs. of White
to cast a face and up to 50 lbs. to do a human torso, unless
it's Uncle Ted, who needs much more.

Another advantage of using the White is the nice consistent
white color of the finished piece. If you use UltraCal 30, you
will have a strong piece, but it will be slightly green. If you
use patching plaster from the hardware store you will get a light
gray with black dots. You can color plasters with any kind of
neutral, water-based pigment. This includes everything from craft
paint to water colors. In some parts of the country you can get
masonry pigments. Personally, I like to mix the color into the
plaster so that if it gets chipped, it won't betray a big white
scar.

Well, that's a brief overview. There's much more to the process
than these simple instructions, but most of that will be picked
up from your first attempt. The learning curve is high with these
materials so don't be afraid to experiment a bit before trying
something big. If you want to attempt a professional-level project
I recommend you get one of the many books
or videos that touch on the
subject.

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